1. Field of the Invention
This invention relates to floor treating pads, and more specifically, to a novel method of making a rotatable floor treating pad of low-density abrasive product. The invention also relates to an elongate strip made as a result of the method, a rotatable pad made by the method and a helix made by conforming the elongate strip into a helical shape.
2. Prior Art
The low-density abrasive products of the type defined in U.S. Pat. No. 2,958,593 and sold under the trade designation "Scotch-Brite" by the 3M Company of St. Paul, Minn. have found a great commerical success in use as floor treating pads. This type of abrasive product is typically formed of crimped staple fibers which have been formed into a mat and impregnated with adhesive and abrasive. The pads are available in any of a wide variety of types to provide many functions. Some pads are extremely abrasive and are desirably used for wax stripping and cleaning floor surfaces which are heavily encrusted with soil. Others are mildly abrasive and are typically used for floor polishing, with or without the prior application of wax.
The pads of this type are typically cut in a circular shape to be used in conjunction with a floor polishing machine. Such machines have a means for engaging or holding the pad therein while rotating the pad against the surface being treated. One highly commercially successful engaging means is that described by Kleemeier et al in U.S. Pat. No. 3,527,001.
The circular pads are typically cut from a larger sheet of the nonwoven abrasive product to form discs. Such a cutting operation, as may be expected, produces a certain amount of wasted material which increases the cost of each individual disc because a certain amount of the material must be discarded. Not only does this increase the cost of production, but it also creates a disposal problem since there is no known economic use for the residue remaining after the discs have been cut.
Certain U.S. patents suggest alternative methods of converting or cutting the nonwoven abrasive product but none has suggested a completely satisfactory solution to the problem. For example, U.S. Pat. No. 3,529,385 discloses making an abrasive brush out of an annulus of endwise stacked rectangular segments of the abrasive product. U.S. Pat. No. 4,004,316 discloses an arrangement of similarly endwise disposed folded segments made of the abrasive material held in place by a rotatable mechanical hub. U.S. Pat. No. 3,181,193 discloses a floor cleaning brush composed of similarly endwise disposed segments of the nonwoven abrasive product in stacked collections between conventional brush segments to form a rotatable annulus. Each of the devices disclosed in these patents requires cutting, stacking and/or assembling of separate segments of nonwoven abrasive material to produce the floor pad or brush. While the segments may be converted or cut with little or no waste, production of the floor pad therefrom requires time-consuming handling steps and/or expensive hubs or other mechanical fastening devices. Moreover, such methods require the endwise orientation of the nonwoven abrasive segments. This prevents the generally more uniformly abrasive original face of the nonwoven abrasive product from being used.
U.S. Pat. No. 3,357,141 discloses a baseboard and floor cleaning brush which employs a single strip of nonwoven abrasive material in either a pleated arrangement in an endwise disposition for use or in a slit helical arrangement with the original face exposed for rotation. The latter-mentioned brush arrangement of this patent, however, would be unsuited for use as a rotatable floor treating pad since it has an inherently weak outer edge which virtually precludes its ability to be used to heel during a cleaning operation. The ability to heel is an essential requirement of a successful commerical cleaning pad. Heeling involves twisting and forcing down the handle of a rotary floor treating machine to permit an edge of the working face of the pad to bear down on a small area, lifting the remaining portion of the working face of the rotary pad off the floor. This causes the full weight of the machine to be directed upon the small area of the edge of the pad.